Propeller.



H. PAEHRMANN.-

PROPBLLER. APPLICATION FILED SEPT. 30.1910."

1,073,413, Y Patented Sept. 16, 1913.

2 SHEETS-SHEET 2.

H. FAEHRMANN.

PROPBLLER.

APPLICATION FILED SEPT. so, 1910.

1,073,411 Patented Sept. 16, 1913` 2 SHEETS-SHEET 1,

' HERMANN FAEHBMANN, 0F NEW YORK, N. Y.

PBOPELLER.

Specification of Letters Patent. Patented Sept. 16, 1913.

Application tiled September 30, 1910. Serial No. 584,6580.

To all 'whom z'zf may concern.'

Be it known'tliat I, HERMANN FAEHRMANN, a citizen of the United States,and resident of the borough of Brooklyn, county of- Kings, city and State of New York, have invented cert-ain new and useful Improvements in Propellers, of which the following is aspeciiication. My invention relates to propellers of the screw type, and is adapted for use especially l in the propulsion of air-ships and boats, but

maybe employed for other pur Uses also.

The object ofmyinvention s to produce a propeller which will be light yet very strong and rigid, so that it may be rotated at a very high rate of s eed. Through experience I have acquirev the conviction that progress and success in aerial navigation will depend largely on the use of high-speed propellers.

To accomplish the above-indicated result, I construct the propeller blades and secure them in a novel manner fully described hereinafter with reference to the accompanying drawings, in which- Figure 1 is an end view of a propeller constructed according to my invention andcom rising two sets of blades; Fig. 2 is a simi ar view of a propeller'comprisingfour sets of blades; Fig. 3 is a longitudinal vertical section, taken through the center of either Fig. 1 or Fig. 2'; Figs. 4 and 5 show one of the blades in edge view and face view respectively; Fig. 6 is a cross section on line 6.--6 of Fig. 5; Fig. 7 shows a propeller of the character representedv in Fig. 2, 1n combination with a lsurrounding rim; Fig. 8 shows a hub with two blades projected at opposite sides thereof; Fig. 9 is a face view, with parts in section,5of a construction 1n which a coil is .used to hold the blades, and Fig. l0 is a similar view of still another construction. In carrying out my invention, the individual blades are narrow, and several of them (six in Fi s. 1,- 2, 3, 7, 9 and 10) form a set which ta es the place of one oir` the wide blades of usual ropellers. These narrow blades A taper rom the center to their outer ends, in order that they may be able to better withstand thestrains produced by centrifugal force and by pressure.

As shown, the pitch angle of the blades is very small, not exceeding 15o, and the use of Isuch a small pitch angle I consider a novel and useful feature of [my invention. The proportion of blade width to blade length is about as 1:3, in the example illustrated. When rotated at high velocities, the strains on the blades are largely tensile strains.

The cross section of the individual bladeswill vary according to the requirements of each-case. I prefer to make the blades with a flat driving surface A and with a round surface A2 on the back, but they could be made concave on the driving side.

Various means may be em loyed for assembling the blades. Accor ing to Figs. 1 to 6, the blades A are provided with segmental feet A8 adapted to engage the 'propeller shaft B. The outer portions of the blades are bent as show'n in Fig. 3 so that the driving surfaces A will stand at the proper angle or pitch to aplane perpendicular to the shaft. The feet A8 alsol form means for spacing the bladesof the 'same set v(see-Fig. 3) and for the sake of greater strength, and particularly to prevent the blades from iiying out radially under the influence of centrifugal force, I employ rings or hubs C engaging the outer surfaces of the feet A and the straight inner portions of the blades A, there being as many hubs asthere are blades in each set, that is to say, six in the particular case illustrated. The rings or hubs C also assist in spacing the blades lengthwise of the shaft. They are placed immediately adjacent to the bent or twisted portions of the blades. A collar or washer D may be provided to engage the blades at one end of each set, the blades and the hub C at the other end being engaged by a nut E screwing onthe shaft. Another nut E screws on the shaft and presses against the washer D. Of course, other means might be employed for clamping or ot-herwise securing the blades in position.

The structure shown in Fig. 3 will hold two sets of blades in position, as shown in Fig. 1., or four sets, as in Fig. 2, or in .fact any number of sets that the peripheral width of the feet A will allow to be placed on the shaft B. As long` as the nut E is loose, all the blades may be adjusted individually,

circumferentially of the shaft, and when they have been given the desired position, they are clamped or locked by tightening the nut E. The outer ends of the blades may bc secured to and held by a fiat rim F Fig. 7) of sufficient width to engage all the blades.

Instead of employing hubs C separate from the blades. I may connect blades .and hubs rigidly. Thus in Fig. 8 the hub C has two blades A4 projected therefrom in.

diametrcally opposite directions, and it will be obvious without further explanation how this construction may be used for a propeller -of the type shown in Fig. 1.

Instead of employing a set of hubs, I may provide a continuous elastic hub or holder C2 of spiral or coiled shape, as shown in F ig.,9, the convolutions yof this coiled hub having a pitch corresponding to that of the blades A and engaging the iat front and curved back of each blade so as to hold it in position. The feet A3 would in this case be oblique to the shaft B. and properly concaved to fit the shaft. VNuts E2. check nuts' E3 and a washer D are shown as means for compressing the coiled hub C2 and thus clamping the blades A in position. Finally, as represented in Fig. 10, the blades (of the sameconstruction as in Fig. 9) are clamped between individual rings orvannular hubs C3 each of which is provided with an angular yrecess C4 disposed obliquely, and adjoining hubs are so placed that their recesses will register to receive and hold the blades. Vhile the drawing seems to show such adjoining hubs in contact with each other, there is in reality a very small space between them` so that the endwise pressure exerted by the nuts E2 will clamp the blades A between the adjacent rings or hubs C3.

It will be understood that Various modifications may be made without departing from the nature of my invention.

While the device has been described as a propeller, it will be evident that it may also be employed as a fan or ventilator and for other purposes, as for pumping, in which case it may be run in the opposite direction.

The improved construction herein disclosed will enable the propeller to be rotated at a very high rate of .speed without danger of bursting or other injury, or of deformation, since the material is subjected chiefly to tensile strains. A very high eiiiciency is thus obtained.

The propeller may be driven direct (that is to say, without interposing a speed-reduction gear) from any high speed motor, such as, for example, a Steam turbine or gasolene engine.

I claim as my invention:

1. A structure adapted for use as a propeller or for other purposes, comprising a shaft, blades mounted thereon at an angle to the axis of rot-ation, and a hub structure having spacing portlons winch extend around the entire circumference of the shaft and separate the blades axially.

2. A structure adapted for use as a propeller or for other purposes, comprising a shaft., blades mounted thereon in spiral relation to each other and provided with segmental feet fitted to the shaft said feet extending lengthwise of the shaft and engaging adjacent blades and means for securing said blades.`

3. A structure adapted for use as a propeller or for other purposes, comprising a shaft, blades mounted thereon in spiral relation to each other, ring-shaped hubs arranged between the blades, and means for holding the blades and hubs together.

4. A structure adapted for use as a propeller or for other purposes, comprising a shaft, blades mounted thereon in spiral relation to each other, ring-shaped hubs arranged between the blades and provided at their edges with recesses to receive the blades and means for holding the blades and hubs together. v

5. A structure adapted for use as a propeller or for other purposes, comprising a shaft, blades mounted thereon in spiral relation to each other and provided with inner portions normal to the shaft and with outer portions oblique thereto, ring-shaped hubs arranged between the inner portions of said blades, and means for holding the blades and hubs together. 6. A structure adapted for use as a propeller or for other purposes, ,comprising a shaft, blades mounted thereon at different points of the shafts length, a ring-shaped hub arranged between the blades, and means for holding the blades and hub together.

7. A structure adapted for use as a propeller or for other purposes, comprising a shaft, annular end hubs on the shaft blades mounted on the shaft at different points of its length between said hubs; a ring-shaped hub arranged between the blades all of said hubs being provided at their edges with recesses to receive the blades, and means for holding the blades and hubs together.

S. A structure adapted for use as a propeller or for other purposes, comprising a shaft, blades mounted thereon at different points of the shafts length and provided with inner portions normal to the shaft and with outer portions oblique thereto, a ringshaped hub arranged between the inner portions of said blades, and means for holding the blades and hub together.

9. A structure adapt-ed for use as a propeller or for other pur oses, ycomprising a shaft, blades mounted t ereon, ring-shaped hubs provided at their edges with recesses to receive the blades, and means for holding together the blades and the hubs.

10. -i structure adapted for use as a propeller or for other purposes, comprising a specieation in the presence of two subscribshaft, blades mounted thereon and provided ing Witnesses.

with feet projecting;- lengthwise of the shaft, HERMANN FAEHRMANN. and ring-shaped hubs arranged `between the Witnesses: 5 blades and surrounding said feet. SYDNEY W. FRY,

In testimony whereofz- I have signed this PAUL J. RICHRATH. 

